feat(examples): add GKE Workload Identity Federation examples #258

Job	Run time
README and docs link check	8s
K8s manifest validation	9s
Python lint and tests (uv)	9m 7s
PR language check (English)	2s
Go build	34s
Go lint	23s
Go test	1m 14s
Performance benchmarks and gates	9m 20s
SBOM generation	18s
	21m 15s

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